"extracting the hierarchical Information is non-trivial"-- I think you're going to run into this issue with any ontology. Having said that, see if you can find data in RDF triples format, which is probably the simplest it's going to get.
– Barry CarterJun 21 '17 at 15:38

building off @BarryCarter's comment here, you should certainly check out wikidata, datasets that wikipedia are using.
– albert♦Jun 21 '17 at 19:51

Although you already selected an answer, what do you want to use this data for? Better answers might still be possible...
– GrimaldiJun 28 '17 at 19:55